supposed to be the illustrator.plist file somewhere.
http://www.adobe.com/support/techdocs/331889.html
is there in: user folder - library - preferences - "Adobe Illustartor Settings" folder?
if there is one, just move it to desktop and restart, see what happens (those are temp files anyway)
you also could try to create new user account in System Preferences and try to open Illustrator after login in as new user.
if it runs under new user, could be some conflict in original user setup.
if it's not working under new user, try deleting and re-installing Illustrator.
applications sometimes quit when there is conflict with other software or settings.